package store

import (
	"context"
	"database/sql"
	"fmt"
	"time"

	"github.com/google/uuid"

	"plumber/internal/store/sqlc"
)

// Postgres implements Store against a sqlc-backed database.
type Postgres struct {
	db *sql.DB
}

// NewPostgres wraps db as a Store.
func NewPostgres(db *sql.DB) *Postgres {
	return &Postgres{db: db}
}

func (p *Postgres) CreateUser(ctx context.Context, u *User) error {
	if u == nil {
		return fmt.Errorf("user: nil")
	}
	if u.Role != RoleUser && u.Role != RoleAdmin {
		return fmt.Errorf("invalid role")
	}
	u.Username = NormalizeUsername(u.Username)
	u.Email = NormalizeEmail(u.Email)
	if u.ID == "" {
		u.ID = uuid.NewString()
	}
	if u.Name == "" {
		u.Name = u.Username
	}
	if u.CreatedAt == "" {
		u.CreatedAt = time.Now().UTC().Format(time.RFC3339)
	}

	if u.Role != RoleAdmin {
		u.db = p.db
		return u.Create(ctx)
	}

	// Bootstrap admin: serialize count+insert so two setup-secret registers
	// cannot both observe zero admins.
	tx, err := p.db.BeginTx(ctx, nil)
	if err != nil {
		return err
	}
	defer tx.Rollback()
	if _, err := tx.ExecContext(ctx, `SELECT pg_advisory_xact_lock($1)`, adminRoleLockKey); err != nil {
		return err
	}
	q := sqlc.New(tx)
	n, err := q.CountAdmins(ctx, string(RoleAdmin))
	if err != nil {
		return err
	}
	role := RoleAdmin
	if n > 0 {
		role = RoleUser
	}
	if err := q.CreateUser(ctx, sqlc.CreateUserParams{
		ID:           u.ID,
		Username:     u.Username,
		Name:         u.Name,
		PasswordHash: u.PasswordHash,
		Role:         string(role),
		Email:        u.Email,
		CreatedAt:    u.CreatedAt,
	}); err != nil {
		return mapUniqueViolation(err)
	}
	if err := tx.Commit(); err != nil {
		return err
	}
	u.Role = role
	u.db = p.db
	return nil
}

func (p *Postgres) UserByID(ctx context.Context, id string) (*User, error) {
	return UserByID(ctx, p.db, id)
}

func (p *Postgres) UserByUsername(ctx context.Context, username string) (*User, error) {
	return UserByUsername(ctx, p.db, username)
}

func (p *Postgres) ListUsers(ctx context.Context, q ListUsersQuery) ([]User, string, string, error) {
	return ListUsers(ctx, p.db, q)
}

func (p *Postgres) CountAdmins(ctx context.Context) (int, error) {
	return CountAdmins(ctx, p.db)
}

func (p *Postgres) SetUserRole(ctx context.Context, id string, role Role) error {
	u := &User{ID: id, db: p.db}
	return u.SetRole(ctx, role)
}

func (p *Postgres) SaveUserProfile(ctx context.Context, u *User) error {
	u.db = p.db
	return u.SaveProfile(ctx)
}

func (p *Postgres) CreatePost(ctx context.Context, post *Post) error {
	post.db = p.db
	return post.Create(ctx)
}

func (p *Postgres) GetPost(ctx context.Context, id string) (*Post, error) {
	return GetPost(ctx, p.db, id)
}

func (p *Postgres) GetPostThread(ctx context.Context, rootID string) (*Post, error) {
	return GetPostThread(ctx, p.db, rootID)
}

func (p *Postgres) GetPostThreadForViewer(ctx context.Context, rootID, viewerID string) (*Post, error) {
	return GetPostThreadForViewer(ctx, p.db, rootID, viewerID)
}

func (p *Postgres) UpdatePost(ctx context.Context, post *Post) error {
	post.db = p.db
	return post.Update(ctx)
}

func (p *Postgres) ListRootPosts(ctx context.Context, postDate, viewerID string) ([]Post, error) {
	return ListRootPosts(ctx, p.db, postDate, viewerID)
}

func (p *Postgres) ListRootPostsByAuthor(ctx context.Context, authorID string) ([]Post, error) {
	return ListRootPostsByAuthor(ctx, p.db, authorID)
}

func (p *Postgres) ListRootPostsAnsweredBy(ctx context.Context, adminID string) ([]Post, error) {
	return ListRootPostsAnsweredBy(ctx, p.db, adminID)
}

func (p *Postgres) SetRootPostState(ctx context.Context, id string, state PostState) error {
	return SetRootPostState(ctx, p.db, id, state)
}

func (p *Postgres) VotePost(ctx context.Context, userID, postID string, value int) error {
	return SetPostVote(ctx, p.db, userID, postID, value)
}